A familiar way to examine elastic bands executed in clothing factories relies on the workmen inserting their hands into the elastic band portions of clothing, such as jacket hems and elasticized waists, and stretching outwards. Operators straighten the wrinkled portions and examine the possible defects by eyes, which is rather tedious. Moreover, after one side of elastic bands is finished, the foregoing actions must be repeated for another examination to the other side. Such an operation is inconvenient and time-wasting. Besides, when a defect is detected, the operator must stretch the elastic band by one hand and trim clothing by the other hand, easily resulting in injuring clothes. Therefore, the conventional method brings much inconvenience to the clothing production.